text: # NVIDIA
  
  import hashlib
  import urllib.request
  import zipfile
  import os
  
  # Download urls
  model_urls = {
    'bert_base_uncased' : ('https://storage.googleapis.com/bert_models/2018_10_18/uncased_L-12_H-768_A-12.zip', 'uncased_L-12_H-768_A-12.zip'),
    'bert_large_uncased' : ('https://storage.googleapis.com/bert_models/2018_10_18/uncased_L-24_H-1024_A-16.zip', 'uncased_L-24_H-1024_A-16.zip'),
    'bert_base_cased' : ('https://storage.googleapis.com/bert_models/2018_10_18/cased_L-12_H-768_A-12.zip', 'cased_L-12_H-768_A-12.zip'),
    'bert_large_cased' : ('https://storage.googleapis.com/bert_models/2018_10_18/cased_L-24_H-1024_A-16.zip', 'cased_L-24_H-1024_A-16.zip'),
    'bert_base_multilingual_cased' : ('https://storage.googleapis.com/bert_models/2018_11_23/multi_cased_L-12_H-768_A-12.zip', 'multi_cased_L-12_H-768_A-12.zip'),
    'bert_large_multilingual_uncased' : ('https://storage.googleapis.com/bert_models/2018_11_03/multilingual_L-12_H-768_A-12.zip', 'multilingual_L-12_H-768_A-12.zip'),
    'bert_base_chinese' : ('https://storage.googleapis.com/bert_models/2018_11_03/chinese_L-12_H-768_A-12.zip', 'chinese_L-12_H-768_A-12.zip')
  }
  
  # SHA256sum verification for file download integrity (and checking for changes from the download source over time)
  bert_base_uncased_sha = {
    'bert_config.json' : '7b4e5f53efbd058c67cda0aacfafb340113ea1b5797d9ce6ee411704ba21fcbc',
    'bert_model.ckpt.data-00000-of-00001' : '58580dc5e0bf0ae0d2efd51d0e8272b2f808857f0a43a88aaf7549da6d7a8a84',
    'bert_model.ckpt.index' : '04c1323086e2f1c5b7c0759d8d3e484afbb0ab45f51793daab9f647113a0117b',
    'bert_model.ckpt.meta' : 'dd5682170a10c3ea0280c2e9b9a45fee894eb62da649bbdea37b38b0ded5f60e',
    'vocab.txt' : '07eced375cec144d27c900241f3e339478dec958f92fddbc551f295c992038a3',
  }
  
  bert_large_uncased_sha = {
    'bert_config.json' : 'bfa42236d269e2aeb3a6d30412a33d15dbe8ea597e2b01dc9518c63cc6efafcb',
    'bert_model.ckpt.data-00000-of-00001' : 'bc6b3363e3be458c99ecf64b7f472d2b7c67534fd8f564c0556a678f90f4eea1',
    'bert_model.ckpt.index' : '68b52f2205ffc64dc627d1120cf399c1ef1cbc35ea5021d1afc889ffe2ce2093',
    'bert_model.ckpt.meta' : '6fcce8ff7628f229a885a593625e3d5ff9687542d5ef128d9beb1b0c05edc4a1',
    'vocab.txt' : '07eced375cec144d27c900241f3e339478dec958f92fddbc551f295c992038a3',
  }
  
  bert_base_cased_sha = {
    'bert_config.json' : 'f11dfb757bea16339a33e1bf327b0aade6e57fd9c29dc6b84f7ddb20682f48bc',
    'bert_model.ckpt.data-00000-of-00001' : '734d5a1b68bf98d4e9cb6b6692725d00842a1937af73902e51776905d8f760ea',
    'bert_model.ckpt.index' : '517d6ef5c41fc2ca1f595276d6fccf5521810d57f5a74e32616151557790f7b1',
    'bert_model.ckpt.meta' : '5f8a9771ff25dadd61582abb4e3a748215a10a6b55947cbb66d0f0ba1694be98',
    'vocab.txt' : 'eeaa9875b23b04b4c54ef759d03db9d1ba1554838f8fb26c5d96fa551df93d02',
  }
  
  bert_large_cased_sha = {
    'bert_config.json' : '7adb2125c8225da495656c982fd1c5f64ba8f20ad020838571a3f8a954c2df57',
    'bert_model.ckpt.data-00000-of-00001' : '6ff33640f40d472f7a16af0c17b1179ca9dcc0373155fb05335b6a4dd1657ef0',
    'bert_model.ckpt.index' : 'ef42a53f577fbe07381f4161b13c7cab4f4fc3b167cec6a9ae382c53d18049cf',
    'bert_model.ckpt.meta' : 'd2ddff3ed33b80091eac95171e94149736ea74eb645e575d942ec4a5e01a40a1',
    'vocab.txt' : 'eeaa9875b23b04b4c54ef759d03db9d1ba1554838f8fb26c5d96fa551df93d02',
  }
  
  bert_base_multilingual_cased_sha = {
    'bert_config.json' : 'e76c3964bc14a8bb37a5530cdc802699d2f4a6fddfab0611e153aa2528f234f0',
    'bert_model.ckpt.data-00000-of-00001' : '55b8a2df41f69c60c5180e50a7c31b7cdf6238909390c4ddf05fbc0d37aa1ac5',
    'bert_model.ckpt.index' : '7d8509c2a62b4e300feb55f8e5f1eef41638f4998dd4d887736f42d4f6a34b37',
    'bert_model.ckpt.meta' : '95e5f1997e8831f1c31e5cf530f1a2e99f121e9cd20887f2dce6fe9e3343e3fa',
    'vocab.txt' : 'fe0fda7c425b48c516fc8f160d594c8022a0808447475c1a7c6d6479763f310c',
  }
  
  bert_large_multilingual_uncased_sha = {
    'bert_config.json' : '49063bb061390211d2fdd108cada1ed86faa5f90b80c8f6fdddf406afa4c4624',
    'bert_model.ckpt.data-00000-of-00001' : '3cd83912ebeb0efe2abf35c9f1d5a515d8e80295e61c49b75c8853f756658429',
    'bert_model.ckpt.index' : '87c372c1a3b1dc7effaaa9103c80a81b3cbab04c7933ced224eec3b8ad2cc8e7',
    'bert_model.ckpt.meta' : '27f504f34f02acaa6b0f60d65195ec3e3f9505ac14601c6a32b421d0c8413a29',
    'vocab.txt' : '87b44292b452f6c05afa49b2e488e7eedf79ea4f4c39db6f2f4b37764228ef3f',
  }
  
  bert_base_chinese_sha = {
    'bert_config.json' : '7aaad0335058e2640bcb2c2e9a932b1cd9da200c46ea7b8957d54431f201c015',
    'bert_model.ckpt.data-00000-of-00001' : '756699356b78ad0ef1ca9ba6528297bcb3dd1aef5feadd31f4775d7c7fc989ba',
    'bert_model.ckpt.index' : '46315546e05ce62327b3e2cd1bed22836adcb2ff29735ec87721396edb21b82e',
    'bert_model.ckpt.meta' : 'c0f8d51e1ab986604bc2b25d6ec0af7fd21ff94cf67081996ec3f3bf5d823047',
    'vocab.txt' : '45bbac6b341c319adc98a532532882e91a9cefc0329aa57bac9ae761c27b291c',
  }
  
  # Relate SHA to urls for loop below
  model_sha = {
    'bert_base_uncased' : bert_base_uncased_sha,
    'bert_large_uncased' : bert_large_uncased_sha,
    'bert_base_cased' : bert_base_cased_sha,
    'bert_large_cased' : bert_large_cased_sha,
    'bert_base_multilingual_cased' : bert_base_multilingual_cased_sha,
    'bert_large_multilingual_uncased' : bert_large_multilingual_uncased_sha,
    'bert_base_chinese' : bert_base_chinese_sha
  }
  
  # Helper to get sha256sum of a file
  def sha256sum(filename):
    h  = hashlib.sha256()
    b  = bytearray(128*1024)
    mv = memoryview(b)
    with open(filename, 'rb', buffering=0) as f:
      for n in iter(lambda : f.readinto(mv), 0):
        h.update(mv[:n])
    return h.hexdigest()
  
  # Iterate over urls: download, unzip, verify sha256sum
  found_mismatch_sha = False
  for model in model_urls:
    url = model_urls[model][0]
    file = model_urls[model][1]
  
    response = urllib.request.urlopen(url)
    
    if not os.path.exists(file):
      print("Downloading", url)
      with open(file, "wb") as handle:
        handle.write(response.read())
    else:
      print(file, "exists, skip downloading.")
  
    print("Unzipping", file)
    zip = zipfile.ZipFile(file, 'r')
    zip.extractall()
    zip.close()
  
    sha_dict = model_sha[model]
    for extracted_file in sha_dict:
      sha = sha_dict[extracted_file]
      if sha != sha256sum(file[:-4] + "/" + extracted_file):
        found_mismatch_sha = True
        print("SHA256sum does not match on file:", extracted_file, "from download url:", url)
      else:
        print(file[:-4] + "/" + extracted_file, "\t", "verified")
  
  if not found_mismatch_sha:
    print("All downloads pass sha256sum verification.")
  
  